This invention relates generally to one-piece initiator devices for use in inflators of vehicular inflatable restraint systems, and, more particularly, to one-piece initiator devices including a permeable fill material providing a controlled gas flow path through the initiator device.
It is well known to protect a vehicle occupant using a cushion or bag, e.g., an “airbag cushion,” that is inflated or expanded with gas such as when the vehicle encounters sudden deceleration, such as in the event of a collision. In such systems, the airbag cushion is normally housed in an uninflated and folded condition to minimize space requirements. Upon actuation of the system, the cushion begins to be inflated, in a matter of no more than a few milliseconds, with gas produced or supplied by a device commonly referred to as an “inflator.”
Many various inflators have been disclosed in the art for the inflating of one or more inflatable restraint system airbag cushions. One category of such inflators is often referred to as “compressed gas inflators” and refers to various inflators which contain a selected quantity of compressed gas. For example, one particular category of compressed gas inflator, commonly referred to as a “stored gas inflator,” simply contains a quantity of a stored compressed gas which is selectively released to inflate an associated airbag cushion. A second category of compressed gas inflator, commonly referred to as “hybrid inflators,” typically supplies or provides inflation gas as a result of a combination of stored compressed gas with combustion products resulting from the combustion of a gas generating material.
Compressed gas inflators typically require undesirably complicated and/or considerably multiple component assemblies which can undesirably increase manufacturing steps and costs. Further, many prior art inflators include a squib or initiator device connected to a gas storage chamber at an opening formed in a base portion of the gas storage chamber to form an enclosure mounted initiator device. One goal of these prior art inflator devices has been to provide a completely hermetic seal or bond between the initiator device and the gas storage chamber base portion. Thus, these prior art inflator devices typically use an impermeable and non-shrinkable material to connect the two components. However, such prior art inflator devices may in some cases develop a gas leak over time, which, because of the hermetically sealed components, is not readily detectable during preassembly testing of the inflator device. Typically, the leaked gas accumulates in a space between the initiator device and a cap positioned at the base portion of the gas storage chamber. As a result of the delayed gas leakage, the inflator device may become non-functional or defective. If installed in an inflatable vehicle restraint system, such an inflator device, upon deployment, may not provide adequate or sufficient inflation gas for the proper inflation of an associated airbag cushion.
There is a need for a more simplified inflator that can be more easily and inexpensively produced. Further, there is a need for an inflator that can be reliably tested before being installed into a vehicle restraint assembly. There is also a need for a more simplified inflator which can be used in various airbag installations and in various vehicular types.
There is also a need for an initiator device that facilitates gas leak detection and has a simplified construction for easier assembly with a corresponding inflator.